I have a new Bryant Evolution systems furnace, AC and Thermostat installed. It seems we have the brand new thermostat SYSTXBBUID01-D.

Our home was steam but 22 years ago converted to forced air. Old 2 stage worked well but new system can not get enough heat to second floor. I have cronologued the heat conditions and find the unit needs to go to High Speed to force air to second floor. Static pressure is well below 1" by Bryant build in system monitor. My installer can not figure out what is needed.

Generally the unit stays on low speed too long. We generally have two conditions:
1. Raising form Night Set Back - it takes 2 hours with fan on low speed to raise temp from 19 to 23 deg C. Unit never goes to High speed with degree by degree rise from 19-23.
2. Normal cycle of heating allows low speed fan to try and satisfy set point. Tech has adjusted time between low speed to High speed (was 10 minutes, now 5 minutes) but this made no difference. Like there thermostat did not adjust. So sometimes the thermostat does get satisfied and no air is pushed up stairs.

I would like the system to go to HS just like the old furnace did. I recongnize this may compromise energy efficiency but we need heat in our bed rooms.

Can you help with this issue? Thanks

Don`t know anything about a Evolution systems furnace, but in most cases with a regular furnace when you speed up the airflow to high the warm air cools off drastically by the time it gets to the room needing warmed up

The evolution will default to low speed if it faults out on lack of air flow on high speed 3 times. You have a restriction in your duct work or the system can not move the cfm needed for its size.